Migrate components/data_reduction_proxy to Mojo interfaces.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index aa41274e9d4c3d901dd114a784aeff9a82c383c4..073ffc2c600a77ae1e1db435138c38b52952b756 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -118,7 +118,7 @@
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/content_settings/core/common/content_settings.h"
 #include "components/content_settings/core/common/content_settings_types.h"
-#include "components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.h"
+#include "components/data_reduction_proxy/content/browser/data_reduction_proxy_host_impl.h"
 #include "components/dom_distiller/core/dom_distiller_switches.h"
 #include "components/dom_distiller/core/url_constants.h"
 #include "components/error_page/common/error_page_switches.h"
@@ -1014,10 +1014,6 @@ void ChromeContentBrowserClient::RenderProcessWillLaunch(
 #if defined(OS_ANDROID)
   host->AddFilter(new cdm::CdmMessageFilterAndroid());
 #endif
-  DataReductionProxyChromeSettings* data_reduction_proxy_settings =
-      DataReductionProxyChromeSettingsFactory::GetForBrowserContext(profile);
-  host->AddFilter(new data_reduction_proxy::DataReductionProxyMessageFilter(
-      data_reduction_proxy_settings));
 
   host->Send(new ChromeViewMsg_SetIsIncognitoProcess(
       profile->IsOffTheRecord()));
@@ -2783,6 +2779,23 @@ void ChromeContentBrowserClient::ExposeInterfacesToRenderer(
     content::RenderProcessHost* render_process_host) {
   registry->AddInterface(
       base::Bind(&startup_metric_utils::StartupMetricHostImpl::Create));
+
+  Profile* profile =
+      Profile::FromBrowserContext(render_process_host->GetBrowserContext());

[dcheng, 2016/07/08 05:50:53]

I think a BrowserContext here should be sufficient.

(If it turns out other things need a Profile later, that's easy enough to
change)

[leonhsl(Using Gerrit), 2016/07/11 14:36:07]

Done and thanks!

+  DataReductionProxyChromeSettings* data_reduction_proxy_settings =
+      DataReductionProxyChromeSettingsFactory::GetForBrowserContext(profile);
+  auto* data_reduction_proxy_host =
+      new data_reduction_proxy::DataReductionProxyHostImpl(
+          data_reduction_proxy_settings
+              ? data_reduction_proxy_settings->Config()
+              : nullptr,
+          render_process_host);

[dcheng, 2016/07/08 05:50:53]

Lines 2789-2791 should probably just be inlined into the host ctor: it's an
implementation detail of the host.

[leonhsl(Using Gerrit), 2016/07/11 14:36:07]

Done.

+  // The data_reduction_proxy_host is a render process host observer, so here we
+  // can use base::Unretained safely.
+  registry->AddInterface(
+      base::Bind(&data_reduction_proxy::DataReductionProxyHostImpl::BindRequest,
+                 base::Unretained(data_reduction_proxy_host)),
+      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));

[dcheng, 2016/07/08 05:50:53]

I'm a bit sad about how the ownership here has become very loosely coupled: we
have to bind an unretained pointer into the callback, and then add a comment
(quite far away from the actual class and easy to become outdated) that it
self-deletes due to being a RenderProcessHostObserver.

As a strawman... how bad would it be:
- Make this a base::Owned() pointer.
- Have the InterfaceRegistry clear registered callbacks on the task runner the
interface factory was registered with

[leonhsl(Using Gerrit), 2016/07/11 14:36:07]

I'm also investigating around,, but I think Ken would have some insights about
this concrete sample from mojo overall point of view. Thanks~

 }
 
 void ChromeContentBrowserClient::RegisterFrameMojoShellInterfaces(